Thermostat



M A. WICKS.

THERMOSTAT. APPLICATION FILED JUNE 1 4. 1920.

Patented Sept 19, 1922.

Waxy??? Wwf Patented Sept. 19, 1922.

UNITED? STATES PATENT OFFICE.

MAURICE A. wIcRs, or DETRoIT, MICHIGAN, ASSIGNOR To KELVINATOR ooRPoRA- TION, 0E DETROIT, MICHIGAN, A. CORPORATION or DELAWARE.

THERMOSTAT.

Application filed June 14, 1920. Serial No. 388,832.

To all whom it may concern:

Be it known that I, MAURIC A. VVIoKs, a citizen of the United States, residing at Detroit. in the county of Vayne and State of Michigan, have invented a certain new and useful Improvement in Thermostats, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings. I

This inventionrelates to thermally controlled elec-tric switches. and is capable of many uses but is especially designed for use in connection with a refrigerating apparatus and hasfor its objects to provide an improved device in which an electric switch is controlled by temperature conditions in the apparatus. this switch in turn controlling an electric motor which drives the compressor of the apparatus and is started or stopped according to predetermined conditions. The objects of the invent-ion are the provision of a simple and compact device which while small in total size shall possess acomparatively large operating chamber, a large volume of volatile agent, a large exposed surface and a construction which shall shield the operating parts from injury either by external shocks or by internal pressure conditions due to excessive or deficient temperature. Other objects are the'provision of a device which can be easily and simply manufactured and adjustedand which shall serve to break a current of considerable size without arcing and without necessitate ing the use of a relay; while further objects and advantages of the invention will become apparent as the description proceeds.

In the drawings accompanying and forming a part of this application I have illustrated one of the many physical structures in which my inventive idea can be embodied although without intent to limitmyself to the particular designs and arrangements therein shown. Fig.1 is a top plan view of my improved thermostat with the switchbox cover removed; Fig. 2 is a vertical sec.- tional view of my improved thermostat; and Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2 and looking in the direction of the arrows.

Describing the parts by reference characters, 1 represents a circular supporting cap preferably having at its margin a rounded helical flange 2 in order that the device may rest snugly upon the. top of a coiled pipe.

Seated on the upper face of this cap and held thereto in any suitable manner as by screws 33 is the switch box 4 here shown as having a removable cover 5 and a flexlble cable 6. Located inside this box is suitable switch mechanism adapted to be actuated by the reciprocation of the rod 7. The particular nature. of the construction of the switch mechanism is not important, that shown herein being of the spring toggle type. The arrangement is such that upon the upward movement of the rod 7 the switch will be closed and the motor started, while upon the downward movement the switch will be opened and the motor stopped.

The rod 7 depends through a hole 10 formed in the cap and surrounded on the lower side by a depending cylindrical wall 11 which external surface is threaded for the reception of the adjusting ring 12. Also depending from the cap outside of this ring are a plurality of tension rods or bolts 13-13 to whosefurther ends is attached the end plate 14. Upon this plate is seated the expansible vessel 15, preferably made with longitudinally expansible, circumferentially corrugated, flexible sheet metal walls, and rigid. end walls 16 and 17. The former is provided with a filling valve 18 :and the latter with a connection adjustably secured to the rod 7. The end wall 17 is formed with spanner openings 2 1 by means of which the same may be turned as is necessary to adjust the device for different temperatures.

It will be noted that actuation of the switch always occurs at the same point of expansion or contraction of the flexible vessel so that the only condition required to be met for such operation is that of the temperature which determines the internal pressure of the vapor contained therein. It will also be noted that the number of parts, both movable and immovable, is very small, and that these are symmetrically arranged resulting in a minimum tendency to bind or get out of order. It will be observed that the end of the wall 11 constitutes a' stop for the expansible vessel and prevents I high temperatures.

undue expansion thereofin case of unduly The device is adjusted so that the switch is actuated just before the vessel reaches this point. It will be understood, also, that many changes in detail can be made, and that I do not limit myself of an operating device projecting through said hole, an expansible metal vessel operatively engaging said devlce,

V a spring surrounding said flange and operatlvely engaging said abutment and opposing the expansion of the vessel, and means securing the further end of sa d vessel to saidsupporting member.

-2. In a thermostat, in combination, a supporting member having on one side an externallythreaded wall and an abutment ring adjustable therealong, an expansible metal vessel coaxial with said wall, a plurality of tension members carried by said member outside of said wall and attached to the further end of the vessel, a spring intercontrolling device op'eratively attached to said vessel and adapted to be actuated before the expansion of the vessel brings it into engagement with said wall.

3. In a thermostat, in combination, an apertured supporting plate, a threaded flange projecting from said plate on one side and surroundingthe aperture, a switch secured to the opposite side of'said plate and overhanging said aperture, a longitudinally expansible, circumferentially-corrugated, cylindric tl metal vessel supported in line with said aperture and having its further end secured at a fixed distance from said plate, the nearer end of said vessel being movable toward and from said plate through a distance which is limited by the end of said flange, an operating rod traversing said aperture and connecting said switch and vessel, a spring surrounding said flange and having one end bearing against the nearer end of said vessel, and a threaded adjusting member screwed to said threads and supporting the opposite end of said spr ng. I

In testimony whereof I hereunto afiix my signature.

MAURICE A. WICKS. 

